All three players are staying in the same hotel in London and while Thiem was recovering from a defeat on Monday and Nadal coming to terms with his season-ending knee injury, Sock was attempting to sleep ahead of his clash with Marin Cilic at 2pm today.

However, they found themselves standing outside in freezing temperatures after the fire alarm was activated in the hotel.

“It was probably one of the most annoying noises I’ve ever heard in my entire life,” Sock said.

“We’re on the second floor of the hotel.

“I guess whatever happened in the hotel was on the second floor.

“I guess from what the workers at the hotel said, the location of your room is how loud the alarm is.

“We are right there, kind of right in the centre of it.

“It literally sounded like the intercom I thought was in our room.

“Super loud, super annoying. It went on for a while.

“At first I didn’t know if it was a test or whatever. Then I realised it was 4am, so I hoped it wasn’t just a test from the hotel.

“I went outside, saw Rafa, saw Dominic. Everyone was all bundled up, freezing cold, just wanting to get back inside.

“Yeah, it was pretty miserable, to be honest.”

However, it didn’t appear to affect Sock as he came through a gruelling three-setter against Cilic, battling back from a set down and 3-0 in the third to seal his first ever ATP World Tour Finals victory.

But the American also said he tried his best to avoid going outside at all, given how cold it was.

“I stayed in the room for a while, which obviously probably isn’t the smartest thing to do, if there had been a real scare,” Sock added.

“Not even sure what the exact reason why the alarm went off.

“But it was unbearable to stay in the room, it was that loud and annoying.

“That’s more the reason why we left. My girlfriend and I left and went outside.

“We saw everyone outside.

“The process, I probably waited in the room for five, seven minutes, then probably outside for another five or seven.